Control method, inspection system, and storage medium

ABSTRACT

According to one embodiment, a control method includes setting a transmission angle of an ultrasonic wave to a standard angle. The control method further includes transmitting an ultrasonic wave at the set transmission angle and detecting an intensity of a reflected wave from an object. The control method further includes calculating a tilt angle based on a gradient of the intensity. The tilt angle indicates a tilt of the object. The control method further includes resetting the transmission angle based on the tilt angle.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is based upon and claims the benefit of priority fromJapanese Patent Application No. 2018-130611, filed on Jul. 10, 2018; theentire contents of which are incorporated herein by reference.

FIELD

Embodiments described herein relate generally to a control method, aninspection system, and a storage medium.

BACKGROUND

There is an inspection method in which an ultrasonic wave is transmittedtoward an object, and the goodness of the state of the object isinspected using a reflected wave from the object. It is desirable todevelop control technology of the inspection method so that theultrasonic wave can be transmitted toward the object at a moreappropriate angle.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic view illustrating an inspection system accordingto a first embodiment;

FIG. 2 is a perspective view illustrating a portion of the inspectionsystem according to the first embodiment;

FIG. 3 is a schematic view illustrating the internal structure of theprobe tip;

FIG. 4 is a schematic view illustrating the configuration of theinspection system according to the first embodiment;

FIG. 5 is a flowchart illustrating the control method according to thefirst embodiment;

FIG. 6 and FIG. 7 are schematic views describing the control methodaccording to the first embodiment;

FIG. 8A to FIG. 8C and FIG. 9 are schematic views illustrating images ofthe weld portion vicinity;

FIGS. 10A and 10B are schematic views describing the control methodaccording to the first embodiment;

FIG. 11 is a schematic view illustrating an inspection system accordingto a second embodiment;

FIG. 12 is a flowchart illustrating a control method according to thesecond embodiment;

FIG. 13 and FIG. 14 are display examples of the inspection systemaccording to the second embodiment;

FIG. 15 is a flowchart illustrating a control method according to athird embodiment; and

FIG. 16 is a schematic view illustrating the configuration of theinspection system according to the third embodiment.

DETAILED DESCRIPTION

According to one embodiment, a control method includes setting atransmission angle of an ultrasonic wave to a standard angle. Thecontrol method further includes transmitting an ultrasonic wave at theset transmission angle and detecting an intensity of a reflected wavefrom an object. The control method further includes calculating a tiltangle based on a gradient of the intensity. The tilt angle indicates atilt of the object. The control method further includes resetting thetransmission angle based on the tilt angle.

Embodiments of the invention will now be described with reference to thedrawings.

The drawings are schematic or conceptual; and the relationships betweenthe thicknesses and widths of portions, the proportions of sizes betweenportions, etc., are not necessarily the same as the actual valuesthereof. The dimensions and/or the proportions may be illustrateddifferently between the drawings, even in the case where the sameportion is illustrated.

In the drawings and the specification of the application, componentssimilar to those described thereinabove are marked with like referencenumerals, and a detailed description is omitted as appropriate.

First Embodiment

FIG. 1 is a schematic view illustrating an inspection system accordingto a first embodiment.

FIG. 2 is a perspective view illustrating a portion of the inspectionsystem according to the first embodiment.

As illustrated in FIG. 1 , the inspection system 100 according to thefirst embodiment includes an inspection apparatus 1 and a processor 2.The inspection apparatus 1 includes a probe 10, an imager 20, a coater30, and a robot arm (hereinbelow, called the arm) 40.

When welding, one member is made by melting and joining portions of twoor more members. The inspection system 100 performs a non-destructiveinspection to check whether or not the portion that is welded(hereinbelow, called the weld portion) is joined appropriately.

The probe 10 includes multiple sensors. The multiple sensors transmitultrasonic waves toward the inspection object (the weld portion) andreceive reflected waves from the object. The imager 20 acquires an imageby imaging the welded member. The imager 20 extracts the weld mark fromthe image and detects the position of the weld portion. The coater 30coats a couplant onto the upper surface of the weld portion. Thecouplant is used to provide acoustic matching of the ultrasonic wavebetween the probe 10 and the object. The couplant may be a liquid or agel.

The probe 10, the imager 20, and the coater 30 are provided at the tipof the arm 40 as illustrated in FIG. 2 . The arm 40 is, for example, anarticulated robot. The positions of the probe 10, the imager 20, and thecoater 30 can be changed by driving the arm 40.

The processor 2 performs various processing based on informationacquired by the inspection apparatus 1. The processor 2 controls theoperations of each component included in the inspection apparatus 1based on the information obtained by the processing. The processor 2includes, for example, a central processing unit (CPU).

The inspection apparatus 1 is connected to the processor 2 by wired orwireless communication. The inspection apparatus 1 may be connected tothe processor 2 via a network. Or, the inspection system 100 may berealized by including the processor 2 in the inspection apparatus 1.

FIG. 3 is a schematic view illustrating the internal structure of theprobe tip.

As illustrated in FIG. 3 , a matrix sensor 11 is provided inside theprobe 10 tip. The matrix sensor 11 includes multiple sensors 12. Thesensors 12 can transmit and receive ultrasonic waves. The sensors 12are, for example, transducers.

The multiple sensors 12 are arranged along a second direction and athird direction; the second direction crosses a first direction in whichthe ultrasonic waves are transmitted; and the third direction crosses aplane parallel to the first direction and the second direction. In theexample of FIG. 3 , the first direction corresponds to a z-direction.The second direction and the third direction correspond respectively toan x-direction and a y-direction. Hereinafter, the case will bedescribed where the first direction, the second direction, and the thirddirection correspond respectively to the mutually-orthogonalz-direction, x-direction, and y-direction.

FIG. 3 illustrates a state of inspecting whether or not a weld portion93 of a member 90 is welded appropriately. The member 90 is made by spotwelding of a first member 91 and a second member 92 at the weld portion93. The weld portion 93 includes a solidified portion 94. The solidifiedportion 94 is formed by melting, mixing, and solidifying a portion ofthe first member 91 and a portion of the second member 92. Each of thesensors 12 transmits an ultrasonic wave US toward the member 90 coatedwith a couplant 95 and receives a reflected wave RW from the member 90.

In one specific example as illustrated in FIG. 3 , the ultrasonic wavesUS are transmitted toward the weld portion 93 from the multiple sensors12. For example, beams of the ultrasonic waves traveling in thez-direction are formed by transmitting the ultrasonic waves US in thez-direction simultaneously from the sensors 12. The ultrasonic waves USare reflected by the upper surface or the bottom surface of the member90. The sensors 12 receive the reflected waves RW. The sensors 12multiply detect the intensities of the reflected waves at a prescribedtime interval.

In another example, one sensor 12 transmits the ultrasonic wave UStoward the weld portion 93. The sensors 12 each receive and detect theintensity of the reflected wave RW. Each of the sensors 12 sequentiallytransmits the ultrasonic wave US. Each time the ultrasonic wave US istransmitted from the sensor 12, the multiple sensors 12 receive thereflected wave RW and detect the intensity at each sensor 12.

The processor 2 determines whether or not the first member 91 and thesecond member 92 are welded appropriately at the weld portion 93 basedon the intensities of the reflected waves RW detected by the sensors 12.

FIG. 4 is a schematic view illustrating the configuration of theinspection system according to the first embodiment.

FIG. 5 is a flowchart illustrating the control method according to thefirst embodiment.

FIG. 6 and FIG. 7 are schematic views describing the control methodaccording to the first embodiment.

As illustrated in FIG. 4 , the processor 2 includes, for example, acontroller 2 a, an acquirer 2 b, a calculator 2 c, and an end determiner2 d.

In step St1 (a setting step), the controller 2 a sets a transmissionangle for transmitting the ultrasonic wave toward the object. In stepSt1, the transmission angle is set to a preset standard angle. If theshape and the orientation of the object O are known, the standard angleis set to a value such that the ultrasonic wave is perpendicularlyincident on the surface of the object. Or, the standard angle may be setto a prescribed value added to the value of perpendicular incidence.After setting the transmission angle, the controller 2 a transmits acontrol signal to the inspection apparatus 1. When the inspectionapparatus 1 receives the control signal, the inspection apparatus 1performs operations to transmit the ultrasonic wave at the transmissionangle.

As illustrated in FIG. 6 , the angle information of a transmission angleθ is represented by a tilt (θ_(x), θ_(y)) with respect to a referenceangle RA. For example, the reference angle RA is equal to the standardangle set as the transmission angle in step St1.

In the inspection apparatus 1, the transmission angle is adjusted bychanging the angle of the probe 10. Or, the transmission angle may beadjusted by controlling the transmitting direction of the ultrasonicbeam. For example, the transmitting direction of the ultrasonic beam maybe adjusted by controlling the driving timing of the sensors 12 arrangedinside the probe 10 without modifying the angle of the probe 10.

In step St2 (a detecting step), the ultrasonic wave is transmitted fromthe probe 10 of the inspection apparatus 1 toward the object at thetransmission angle set in step St1 in a state in which the probe 10contacts the weld portion 93. The probe 10 detects the intensity of thereflected wave from the object. The ultrasonic wave is stronglyreflected at boundaries of materials having mutually-different acousticimpedances.

For example, as illustrated in FIG. 7 , the first member 91 has a firstsurface S1 and a second surface S2. The first surface S1 is positionedbetween the probe 10 and the second surface S2. The weld portion 93 hasa third surface S3 and a fourth surface S4. The third surface S3 ispositioned between the probe 10 and the fourth surface S4. In regionsother than the weld portion 93, the ultrasonic wave US is reflectedstrongly by the first surface S1 and the second surface S2 of the firstmember 91. At the weld portion 93, the ultrasonic wave US is reflectedstrongly by the third surface S3 and the fourth surface S4.

When the ultrasonic wave is reflected strongly by some surface and thereflected wave is received by the sensor 12, the reflected waveintensity increases temporarily. In other words, the peak of thereflected wave intensity is detected by each sensor 12. The time fromwhen the ultrasonic wave is transmitted from the probe 10 until the peakof the intensity of the reflected wave is detected by the probe 10 isdependent on the position in the z-direction of the surface.Accordingly, the position of the surface strongly reflecting theultrasonic wave can be verified by detecting the peak of the reflectedwave intensity using the sensor 12.

The reflected wave RW undergoes multiple reflection between the firstsurface S1 and the second surface S2 of the first member 91 and betweenthe third surface S3 and the fourth surface S4 of the weld portion 93.As a result, the peaks of the intensity of the reflected wave aremultiply detected by the sensor 12.

There are cases where the fourth surface S4 of the weld portion 93 isnot flat. This is due to the solidified portion 94 included in the weldportion 93, shape deformation during welding, etc. In such a case, it isdesirable for the ultrasonic wave US to be transmitted, on average,along a direction perpendicular to the fourth surface S4. Thereby, theultrasonic wave can be reflected more strongly by the fourth surface S4;and the accuracy of the inspection can be increased.

The acquirer 2 b acquires, from the inspection apparatus 1, informationincluding the transmission angle and the reflected wave intensitiesdetected by the sensors 12. The acquirer 2 b may generate an image basedon the acquired reflected wave intensities.

FIG. 8A to FIG. 8C and FIG. 9 are schematic views illustrating images ofthe weld portion vicinity.

FIG. 8A illustrates an image of the weld portion imaged by the imager20. FIG. 8B illustrates an image corresponding to an A-A′ cross sectionof FIG. 8A. FIG. 8C illustrates an image corresponding to a B-B′ crosssection of FIG. 8A. FIG. 9 illustrates the entire image. As illustratedin FIG. 9 , the image is volume data storing the values at eachthree-dimensional position.

The image of FIG. 8B illustrates the reflected wave intensity at eachpoint in the x-direction and the z-direction. The position in thez-direction corresponds to the time when the reflected wave intensitywas detected. In other words, the image of FIG. 8B is based on theresults of the reflected wave intensities multiply detected by themultiple sensors 12 arranged in the x-direction. The image of FIG. 8Cillustrates the reflected wave intensity at each point in they-direction and the z-direction. Similarly to FIG. 8B, the position inthe z-direction of the image of FIG. 8C corresponds to the time when thereflected wave intensity was detected. The luminance at each point(pixel) included in the images of FIG. 8B, FIG. 8C, and FIG. 9corresponds to the intensity of the reflected wave. A higher luminanceand a whiter color (a lower dot density) means that the intensity of thereflected wave is higher.

In the images, portions exist where pixels having relatively highluminances are continuous in directions crossing the z-direction. InFIG. 8B and FIG. 8C, some of such portions are illustrated as portionsp1 to p4. The portions p1 to p4 show surfaces where the ultrasonic waveis reflected strongly.

It can be seen from FIG. 8B and FIG. 8C that the position in thez-direction where the surface is detected is different between the weldportion 93 and a location other than the weld portion 93. For example,in the image of FIG. 8B, the position in the z-direction of the portionp1 is different from the position in the z-direction of the portion p2.In the image of FIG. 8C, the position in the z-direction of the portionp3 is different from the position in the z-direction of the portion p4.This is due to the position in the z-direction of the bottom surface(the second surface S2) of the location other than the weld portion 93being different from the position in the z-direction of the bottomsurface (the fourth surface S4) of the weld portion 93.

As illustrated in FIG. 7 , the distance between the first surface S1 andthe second surface S2 of the first member 91 is different from thedistance between the third surface S3 and the fourth surface S4 of theweld portion 93. Accordingly, the detection interval of the surface inthe z-direction is different between the weld portion 93 and thelocation other than the weld portion 93.

In step St3 (a calculation step), the calculator 2 c calculates the tiltangle indicating the tilt of the object based on the gradient of thereflected wave intensity detected by step St2. Specifically, step St3includes steps St3 a and St3 b.

In step St3 a, the gradient of the reflected wave intensity iscalculated at each point inside the prescribed region inthree-dimensional space defined by the x-direction, the y-direction, andthe z-direction. In the case where images such as those illustrated inFIG. 8A to FIG. 9 are generated based on the reflected wave intensities,this processing corresponds to calculating the gradient of the pixelvalue for each pixel inside the prescribed region.

The intensity of the reflected wave at coordinates (x, y, z) is taken asI(x, y, z). The prescribed region is, for example, a region havingcoordinates satisfying x1≤x≤x2, y1≤y≤y2, and z1≤z≤z2 for the constantsx1, x2, y1, y2, z1, and z2. It is desirable to designate x1, x2, y1, andy2 so that the prescribed region is included in the weld portion 93. Theexterior form of the designated region may be a rectangle, a circle, orany other shape. For example, the range in the z-direction is designatedso that the shallow region where the bottom surface (the fourth surfaceS4) of the weld portion 93 does not appear is excluded, and so that thewaves multiply reflected by the fourth surface S4 appear once. Regionsr1 and r2 of FIG. 8B and FIG. 8C are examples of the set region.

The gradient of the reflected wave intensity is calculated by thefollowing Formula 1.

G(x,y,z)=(I(x+1,y,z)−I(x,y,z),I(x,y+1,z)−I(x,y,z),I(x,y,z+1)−I(x,y,z))  [Formula1]

G(x, y, z) is a three-dimensional vector representing the gradient ofthe reflected wave intensity in the x-direction, the y-direction, andthe z-direction for the coordinates (x, y, z). Formula 1 calculates thegradient using forward differences. General gradient calculation methodssuch as backward differences, central differences, etc., also may beused.

In step St3 b, the tilt angle that indicates the tilt of the weldportion 93 is calculated based on the gradient of the reflected waveintensity. First, the average of the gradient calculated for theprescribed region described above is calculated. This is called theaverage gradient. The method for calculating the average gradient is notlimited to a simple average and may be a weighted average.

For example, the weight that is used is increased as the x coordinateand the y coordinate approach the center of the prescribed region. The xcoordinate and the y coordinate of the center of the prescribed regionare ((x1+x2)/2, (y1+y2)/2). Thereby, the effects of the region otherthan the weld portion 93 on the average processing can be reduced. Or,the weight that is used may be increased as the value of G(x, y, z)increases. Or, the weight may be based on information relating to theinspection object. For example, the weight that is used may be increasedas the z-direction coordinate approaches the position where the fourthsurface S4 of the weld portion 93 is predicted to appear. Thereby, theaverage processing can be based more on the reflected waves from thefourth surface S4 of the weld portion 93. Or, the average processingdescribed above may be replaced with processing that calculates themedian.

The difference angle that indicates the tilt of the weld portion 93 withrespect to the transmission angle is calculated using the averagegradient described above. The average gradient is written as GM. First,the scale information is excluded from the average gradient; and thetwo-dimensional vector of the following formula showing the directioninformation is calculated.

(GM(x)/GM(z),GM(y)/GM(z))  [Formula 2]

GM(x), GM(y), and GM(z) are respectively the x-, y-, and z-directioncomponents of the average gradient. The θ_(x) component of thedifference angle is calculated from the first component of Formula 2;and the θ_(y) component of the difference angle is calculated from thesecond component of Formula 2. The calculation may be performed bysolving backward from the detection pitch of the reflected waveintensity in the x-direction, the y-direction, and the z-direction.

Or, the probe 10 may be used beforehand to detect the reflected waveswhile tilting the weld portion 93 at various angles. A table of therelationship between the difference angle and the first component andthe second component of Formula 2 is made based on the detectionresults. The angles are calculated using the table. Or, the calculationrelationship may be stored as a regression equation. Then, the tiltangle that corresponds to the tilt of the object is calculated byreversing the sign of the difference angle and adding the result to thecurrent transmission angle.

Arrow A1 of the image of FIG. 8B illustrates the gradient of thereflected wave intensity in the X-Z plane. Similarly, arrow A2 of theimage of FIG. 8C illustrates the gradient of the reflected waveintensity in the Y-Z plane.

The tilt angle may be referenced to the reference angle RA as describedabove, or may be an angle made by reversing the sign of the differenceangle with respect to the transmission angle at that point in time. Forexample, the difference between the transmission angle and thecalculated tilt of the surface of the object may be calculated as thetilt angle. Such a difference also substantially indicates the tilt ofthe object.

In step St4 (a determining step), the end determiner 2 d determineswhether or not to end the acquisition of the image. Step St5 (aresetting step) is performed if the end has not been determined. In stepSt5, the controller 2 a resets the transmission angle based on the tiltangle calculated in step St3. The controller 2 a transmits, to theinspection apparatus 1, a control signal including the resettransmission angle. Thereby, step St2 is performed again. In otherwords, a first loop that includes step St2, step St3, step St4, and stepSt5 is performed repeatedly until the end is determined in step St4.

For example, the end is determined in step St4 when step St2 or step St3has been repeated a prescribed number of times.

In another example, the tilt angle that is calculated in step St3 isstored for each repetition. The end is determined when the calculationresult of the tilt angle is determined to be converging. For example,the first loop is multiply performed; and a first tilt angle iscalculated by the nth step St3. A second tilt angle is calculated by the(n+1)th step St3. The difference between the second tilt angle and thefirst tilt angle is calculated; and the end is determined when thedifference becomes smaller than a prescribed value. The differencebetween the second tilt angle and the first tilt angle is, for example,the sum of the absolute value of the difference between the θ_(x)components and the absolute value of the difference between the θ_(y)components.

For example, in step St5, the tilt angle is used as-is as a transmissionangle θ_(NEXT) that is newly set.

Or, the transmission angle θ_(NEXT) may be set using the currenttransmission angle θ and the tilt angle. For example, the differencebetween the transmission angle θ_(NEXT) and the transmission angle θ maybe set to be larger than the difference between the tilt angle and thetransmission angle θ. At this time, the difference for at least one ofthe θ_(x) component or the θ_(y) component is set to be larger. Thereby,the tilt angle is recalculated to be an angle that is different from thetransmission angle θ and near the predicted tilt of the weld portion 93.The accuracy of the tilt angle calculated next can be increased thereby.The change amount of the angle can be set to be larger if the calculatedtilt angle is smaller than the actual tilt of the weld portion 93 due tothe detection accuracy of the reflected wave intensity, etc. Thereby,the convergence of the repeatedly-calculated tilt angle can be faster.

In particular, there are many cases where the transmission angle θ doesnot converge while the number of updates of the transmission angleθ_(NEXT) is low. Accordingly, until step St5 is performed a prescribednumber of times, it is desirable to set the transmission angle θ_(NEXT)so that the difference between the transmission angle θ_(NEXT) and thetransmission angle θ is larger than the difference between the tiltangle and the transmission angle θ. After the prescribed number oftimes, for example, it is desirable to set the transmission angleθ_(NEXT) so that the difference between the transmission angle θ_(NEXT)and the transmission angle θ is the same as the difference between thetilt angle and the transmission angle θ.

FIGS. 10A and 10B are schematic views describing the control methodaccording to the first embodiment.

In FIGS. 10A and 10B, the horizontal axis is the θ_(x) component; andthe vertical axis is the θ_(y) component. FIG. 10A illustrates thetransition of the transmission angle in the case where the tilt anglethat is calculated as the transmission angle θ_(NEXT) is used as-is.FIG. 10B illustrates the transition of the transmission angle in thecase where the initial transmission angle θ_(NEXT) is set so that thedifference between the transmission angle θ_(NEXT) and the transmissionangle θ is 2 times the difference between the tilt angle and thetransmission angle θ.

As in the transmission angles θ, θ1, and θ2 illustrated in FIG. 10A,there are cases where the transmission angle slowly converges toward anactual tilt angle θ0 of the weld portion 93 if the detection accuracy ofthe reflected wave intensity is low. For such a case, the methoddescribed above can cause the transmission angle to converge rapidlytoward the tilt angle θ0 as in the transmission angles θ and θ3illustrated in FIG. 10B. Thereby, the number of times the first loop isperformed can be low; and the time necessary for the inspection can beshortened.

As another example, the tilt angle is stored for each repetition; andthe transmission angle θ_(NEXT) is calculated based on the tilt anglescalculated for a prescribed number of repetitions. For example, θ_(NEXT)is calculated using the average of the tilt angles calculated for theprescribed number of repetitions.

Step St6 is performed when the end is determined in step St4. In stepSt6, it is determined whether or not step St2 was performed in the statein which the transmission angle is set to a derived angle. The derivedangle is derived based on the tilt angles calculated up to this point,and is the angle estimated to correspond to the tilt of the object. Forexample, the tilt angle that is calculated directly previously is set asthe derived angle. This is because the tilt angle that is calculateddirectly previously is considered to be most proximal to the actual tiltof the object. Or, the average of the multiple tilt angles calculateddirectly previously may be set as the derived angle. Step St7 and stepSt8 are performed in the case where step St2 has not been performed inthe state in which the transmission angle is set to the derived angle.In step St7, the transmission angle is set to the derived angle. In stepSt8, similarly to step St2, the ultrasonic wave is transmitted towardthe object at the set transmission angle; and the intensity of thereflected wave is detected. An image may be generated based on thedetection results of step St8.

The inspection ends after step St8 or in the case where step St2 alreadyhas been performed with transmission angle set to the derived angle.

As described above, the results of the inspection of whether or not thewelding is performed appropriately is affected by the angle of theultrasonic wave transmitted toward the member 90. An inspectionperformed with the probe 10 at an inappropriate angle may determine thejoint to be an incomplete weld even though the actual joint is weldedappropriately. Therefore, it is desirable for the angle of the probe 10to be set to the appropriate value.

Higher perpendicularity of the transmission angle of the ultrasonic wavewith respect to the surface of the object provides a higher intensity ofthe ultrasonic wave reflected by the surface, and a higher accuracy ofthe detection of the position of the surface. It is therefore desirablefor the transmission angle to be set to be perpendicular to the surfaceof the weld portion 93 which is the object.

According to the inspection system 100 and the control method accordingto the first embodiment as described above, the tilt angle thatindicates the tilt of the inspection object is calculated based on thegradient of the reflected wave intensity. A tilt angle that is near theactual tilt of the object can be calculated by using the gradient of thereflected wave intensity. The angle of the ultrasonic wave transmittedtoward the object can be set to a more appropriate value by setting thetransmission angle based on the calculated tilt angle. Thereby, theaccuracy of the inspection can be increased. Or, the appropriatetransmission angle can be found more rapidly when resetting thetransmission angle until the appropriate inspection result is obtained;and the time necessary for the inspection can be shortened.

Here, an example is described in which the weld portion 93 is inspectedusing the inspection system 100 and the control method according to thefirst embodiment. The inspection system 100 and the control methodaccording to the first embodiment also can inspect objects other thanweld portions. For example, the inspection of the strain of the backsurface of a metal container that cannot be visually confirmed from theoutside, etc., can be performed. According to the embodiment, for suchinspections as well, the accuracy of the inspection can be increased; orthe time necessary for the inspection can be shortened.

Second Embodiment

FIG. 11 is a schematic view illustrating an inspection system accordingto a second embodiment.

FIG. 12 is a flowchart illustrating a control method according to thesecond embodiment.

The inspection system 200 according to the second embodiment furtherincludes a displayer 3. For example, the displayer 3 has a wired orwireless connection to the processor 2. The displayer 3 displaysinformation acquired by the inspection apparatus 1 or informationprocessed by the processor 2. The displayer 3 includes, for example, adisplay, a touch panel, or a printer.

The control method according to the second embodiment further includesstep St11 as illustrated in FIG. 12 . Each time step St2 is performed,at least one of the imaging angle or the transmission angle at thatpoint in time is displayed by the displayer 3 in step St11.

FIG. 13 and FIG. 14 are display examples of the inspection systemaccording to the second embodiment.

For example, as illustrated in FIG. 13 , a graph for plotting θ_(x) andθ_(y) of the transmission angle are displayed on the display of thedisplayer. The transmission angle and its number are plotted each timesteps St2 and St3 are performed. Thereby, the user can easily confirmthe transition of the transmission angle. The tilt angle may be plottedsimilarly. Thereby, the user can confirm easily whether or not the tiltangle is converging or the tilt angle is being calculated surely. Or,other than the plotting method described above, the history may bedisplayed in text form.

As another display example, the tilt angle is calculated for eachcoordinate in the x-direction and the y-direction by processing similarto that of step St3; and the tilt angle is displayed for eachcoordinate. FIG. 14 is such an example. In FIG. 14 , the luminance ofeach point shows the tilt at that point. A legend L of the angle isdisplayed at the lower right of FIG. 14 . FIG. 14 illustrates a state inwhich different tilt angles are calculated between the weld portion 93at the image center and the non-weld portion at the periphery of theweld portion 93. By such a display, the user can easily ascertain theexterior form of the weld portion 93 (the tilt of the fourth surfaceS4).

Both the graph illustrated in FIG. 13 and the image illustrated in FIG.14 may be displayed. For example, in the case where the fourth surfaceS4 of the weld portion 93 is curved, etc., the inspection time mayincrease due to a higher number of calculations of the tilt angle. Insuch a case, the display of both the graph illustrated in FIG. 13 andthe image illustrated in FIG. 14 can allow the user to easily ascertainthe higher number of calculations and the reason for the increase.

Third Embodiment

FIG. 15 is a flowchart illustrating a control method according to athird embodiment.

As illustrated in FIG. 15 , the control method according to the thirdembodiment further includes steps St21, St22, and St23.

In step St21, it is determined whether or not the detection resultobtained in step St2 satisfies the inspection condition. If thedetermination is “pass” in step St21, the determination of theinspection is “pass” in step St22; and the processing ends. Step St3 isperformed if the determination is “fail” in step St21. Step St23 isperformed after step St6 or St8. In step St23, pass or fail isdetermined based on whether or not the detection result obtained in stepSt8 satisfies the inspection condition.

For example, the inspection condition is set to be when the distancebetween the peaks of the reflected wave intensities adjacent to eachother in the z-direction is a prescribed threshold or more. Asillustrated in FIG. 3 , the distance between the third surface S3 andthe fourth surface S4 of the weld portion 93 is longer than the distancebetween the first surface S1 and the second surface S2 of the firstmember 91. The peak of the reflected wave intensity in the z-directioncorresponds to the position of the surface. Accordingly, the distancebetween the peaks of the reflected wave intensities detected when thewelding is appropriate is longer than the distance between the peakscorresponding to the first surface S1 and the second surface S2 of thefirst member 91. For example, the threshold is set based on the distancebetween the first surface S1 and the second surface S2 of the firstmember 91 or the distance between the third surface S3 and the fourthsurface S4 of the weld portion 93.

For example, the distance between the peaks of the reflected waveintensities detected at each point (each sensor 12) in the x-directionand the y-direction is compared to the prescribed threshold. Then, thenumber of points where the distance between the peaks is the thresholdor more is counted. Continuing, it is determined that the joint isappropriate if the count meets or exceeds another preset threshold.

According to the method illustrated in FIG. 15 , the inspection ends atthe point in time when the inspection condition is passed. Therefore,the inspection can be ended earlier.

FIG. 16 is a schematic view illustrating the configuration of theinspection system according to the third embodiment.

In the inspection system 300 according to the third embodiment, theprocessor 2 further includes a goodness determiner 2 e. The goodnessdeterminer 2 e performs steps St21, St22, and St23.

In the example illustrated in FIG. 16 , the inspection system 300further includes the displayer 3. As described above, the displayer 3displays the transition of the transmission angle or the tilt angle.Further, the goodness determiner 2 e may transmit the determinationresult to the displayer 3. The displayer 3 receives and displays thedetermination result.

A case is described in the example hereinabove where the reflected waveintensity is multiply detected by the multiple sensors 12 arranged inthe second direction and the third direction. Three-dimensional volumedata is acquired by this method. The embodiments are not limited to theexample; and two-dimensional data may be acquired using the multiplesensors 12. For example, the reflected wave intensity may be multiplydetected by the multiple sensors 12 arranged in the second direction orthe third direction. In such a case, the component of the adjustedtransmission angle is one of θ_(x) or θ_(y). Even in such a case, byusing the method according to the embodiments described above, a moreappropriate θ_(x) or θ_(y) can be found in a shorter length of time; andthe time necessary for the inspection can be shortened.

According to the embodiments described above, a control method and aninspection system can be provided in which the angle of the ultrasonicwave transmitted toward the object in the inspection can be set to amore appropriate value. The angle of the ultrasonic wave transmittedtoward the object in the inspection can be set to a more appropriatevalue by using a program for causing a system to implement theembodiments described above, or by using a storage medium in which theprogram is stored.

The embodiments may include the following aspects.

Aspect 1

A control method, comprising:

-   -   setting a transmission angle of an ultrasonic wave to a standard        angle;    -   transmitting an ultrasonic wave at the transmission angle and        detecting, at multiple points, an intensity of a reflected wave        from an object, the multiple points being arranged along a        second direction and a third direction, the second direction        crossing a first direction, the ultrasonic wave being        transmitted in the first direction, the third direction crossing        a plane including the first direction and the second direction;        and    -   displaying a gradient of the intensity for each of the multiple        points.

In the specification of the application, “perpendicular” and “parallel”refer to not only strictly perpendicular and strictly parallel but alsoinclude, for example, the fluctuation due to manufacturing processes,etc. It is sufficient to be substantially perpendicular andsubstantially parallel.

Hereinabove, embodiments of the invention are described with referenceto specific examples. However, the invention is not limited to thesespecific examples. For example, one skilled in the art may similarlypractice the invention by appropriately selecting specificconfigurations of components such as the inspection apparatus and theprocessor, etc., from known art; and such practice is within the scopeof the invention to the extent that similar effects can be obtained.

Further, any two or more components of the specific examples may becombined within the extent of technical feasibility and are included inthe scope of the invention to the extent that the purport of theinvention is included.

Moreover, all control methods, all inspection systems, and all storagemediums practicable by an appropriate design modification by one skilledin the art based on the control methods, the inspection systems, and thestorage mediums described above as embodiments of the invention also arewithin the scope of the invention to the extent that the spirit of theinvention is included.

Various other variations and modifications can be conceived by thoseskilled in the art within the spirit of the invention, and it isunderstood that such variations and modifications are also encompassedwithin the scope of the invention.

While certain embodiments have been described, these embodiments havebeen presented by way of example only, and are not intended to limit thescope of the inventions. Indeed, the novel embodiments described hereinmay be embodied in a variety of other forms; furthermore, variousomissions, substitutions and changes in the form of the embodimentsdescribed herein may be made without departing from the spirit of theinventions. The accompanying claims and their equivalents are intendedto cover such forms or modifications as would fall within the scope andspirit of the invention.

1. A control method, comprising: setting a transmission angle of anultrasonic wave to a standard angle; transmitting an ultrasonic wave atthe set transmission angle and detecting an intensity of a reflectedwave from an object; calculating a tilt angle based on a gradient of theintensity, the tilt angle indicating a tilt of the object; and resettingthe transmission angle based on the tilt angle. 2-10. (canceled)